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What PhD students really want  [PDF]
Minnie Mao
Physics , 2010,
Abstract: The road to becoming an astronomer is exciting, but often fraught with danger and conflicting messages. A PhD student is inundated with catch-phrases such as "publish or perish" and "it's not about the quantity, but the quality of work". How do we know which advice to follow? How can we publish copious amounts of quality work in only three years so as to maximize our success in the future? How do we even know what "good quality" really is? With only a short time to prepare ourselves for the big wide world of Astronomy, what is the best way for a PhD student to maximize their research and ultimately maximize their success as a real astronomer? The PhD students of today are the astronomers of tomorrow, but their journey depends on a positive work environment in which they can thrive and improve. Here I present the results of a survey of current PhD students on how they believe they can maximize their success in science. I find that PhD students in Australia expect to write more papers during their PhD than is expected by their supervisors, but that they are generally happy with the quality of their supervision. Above all, students love telescopes, and hands-on observations are an important part of acquiring the knowledge and culture necessary to becoming a real astronomer.
What is Visualization Really for?  [PDF]
Min Chen,Luciano Floridi,Rita Borgo
Computer Science , 2013, DOI: 10.1007/978-3-319-07121-3_5
Abstract: Whenever a visualization researcher is asked about the purpose of visualization, the phrase "gaining insight" by and large pops out instinctively. However, it is not absolutely factual that all uses of visualization are for gaining a deep understanding, unless the term insight is broadened to encompass all types of thought. Even when insight is the focus of a visualization task, it is rather difficult to know what insight is gained, how much, or how accurate. In this paper, we propose that "saving time" in accomplishing a user's task is the most fundamental objective. By giving emphasis to saving time, we can establish a concrete metric, alleviate unnecessary contention caused by different interpretations of insight, and stimulate new research efforts in some aspects of visualization, such as empirical studies, design optimisation and theories of visualization.
Was ist Really Simple Syndication - RSS? / What is Really Simple Syndication - RSS?
Obst, Oliver
GMS Medizin-Bibliothek-Information , 2006,
Abstract: The new magic word for efficient information exchange is RSS - Really Simple Syndication. Within a short time, RSS experienced a rapid spreading to become the fourth exchange form for information in the Internet - beside E-Mail, HTML, and PDF. RSS is based on XML and - according to Wikipedia - comes first at the area of the semantic Web. With RSS the reversal and control of the information flow are possible. Numerous libraries and scientist make usage of Weblogs or RSS feeds for communication with their customers and colleagues.
What Really Causes Necrotising Enterocolitis?  [PDF]
Thomas Peter Fox,Charles Godavitarne
ISRN Gastroenterology , 2012, DOI: 10.5402/2012/628317
Abstract: Background. One of the most serious gastrointestinal disorders occurring in neonates is necrotising enterocolitis (NEC). It is recognised as the most common intra-abdominal emergency and is the leading cause of short bowel syndrome. With extremely high mortality and morbidity, this enigmatic disease remains a challenge for neonatologists around the world as its definite aetiology has yet to be determined. As current medical knowledge stands, there is no single well-defined cause of NEC. Instead, there are nearly 20 risk factors that are proposed to increase the likelihood of developing NEC. Aims and Objectives. The aim of this project was to conduct a comprehensive literature review around the 20 or so well-documented and less well-documented risk factors for necrotising enterocolitis. Materials and Methods. Searches of the Medline, Embase, and Science direct databases were conducted using the words “necrotising enterocolitis + the risk factor in question” for example, “necrotising enterocolitis + dehydration.” Search results were ordered by relevance with bias given to more recent publications. Conclusion. This literature review has demonstrated the complexity of necrotising enterocolitis and emphasised the likely multifactorial aetiology. Further research is needed to investigate the extent to which each risk factor is implicated in necrotising enterocolitis. 1. Background One of the most serious disorders and the single most serious gastrointestinal disorder occurring in neonates is necrotising enterocolitis [1–3]. This enigmatic disease remains a challenge for neonatologists around the world as its definite aetiology has yet to be determined. It is recognised as the most common intra-abdominal emergency effecting neonates and it is the leading cause of short bowel syndrome [4, 5]. Necrotising enterocolitis is characterised by the bowel wall necrosis of variable thickness, which leads to perforation in up to one-third of cases [6]. The condition was first described by Paltauf in 1888 but the term “necrotising enterocolitis” was used for the first time by Schmid and Quaiser in 1953 [7, 8]. Since then, there has been a tremendous increase in the incidence of NEC. This has been attributed largely to two factors. The first is the increase in the number of premature births by Caesarean section for therapeutic reasons resulting in the delivery of premature babies. The second reason is due to the advancement in technology of neonatal care, for example, intensive care units and surfactant therapy have enabled most premature babies to overcome a number of
Is the Notion of Time Really Fundamental?  [PDF]
Florian Girelli,Stefano Liberati,Lorenzo Sindoni
Symmetry , 2011, DOI: 10.3390/sym3030389
Abstract: From the physics point of view, time is now best described through General Relativity as part of space-time, which is a dynamical object encoding gravity. Time possesses also some intrinsic irreversibility due to thermodynamics and quantum mechanical effects. This irreversibility can look puzzling since time-like loops (and hence time machines) can appear in General Relativity (for example in the G?del universe, a solution of Einstein’s equations). We take this apparent discrepancy as a warning bell, pointing out that time as we understand it might not be fundamental and that whatever theory lying beyond General Relativity may not include time as we know it as a fundamental structure. We propose therefore, following the philosophy of analog models of gravity, that time and gravity might not be fundamental per se, but only emergent features. We illustrate our proposal using a toy-model where we show how the Lorentzian signature and Nordstr?m gravity (a diffeomorphisms invariant scalar gravity theory) can emerge from a timeless non-dynamical space. This article received the fourth prize at the essay competition of the Foundational Questions Institute on the nature of time.
Is the notion of time really fundamental?  [PDF]
Florian Girelli,Stefano Liberati,Lorenzo Sindoni
Physics , 2009,
Abstract: From the Physics point of view, time is now best described through General Relativity, as part of space-time which is a dynamical object encoding gravity. Time possesses also some intrinsic irreversibility due to thermodynamics, quantum mechanical effects... This irreversibility can look puzzling since time-like loops (and hence time machines) can appear in General Relativity (for example in the Goedel universe, a solution of Einstein's equations). We take this apparent discrepancy as a warning bell pointing to us that time as we understand it, might not be fundamental and that whatever theory, lying beyond General Relativity, may not include time as we know it as a fundamental structure. We propose therefore, following the philosophy of analog models of gravity, that time and gravity might not be fundamental per se, but only emergent features. We illustrate our proposal using a toy-model where we show how the Lorentzian signature and Nordstroem gravity (a diffeomorphisms invariant scalar gravity theory) can emerge from a timeless non-dynamical space.
The physical and compositional properties of dust: what do we really know?  [PDF]
Ant Jones
Physics , 2014,
Abstract: Many things in current interstellar dust studies are taken as well understood givens by much of the community. For example, it is widely held that interstellar dust is made up of only three components, i.e., astronomical silicates, graphite and polycyclic aromatic hydrocarbons, and that our understanding of these is now complete and sufficient enough to interpret astronomical observations of dust in galaxies. To zeroth order this is a reasonable approximation. However, while these three pillars of dust modelling have been useful in advancing our understanding over the last few decades, it is now apparent that they are insufficient to explain the observed evolution of the dust properties from one region to another. Thus, it is time to abandon the three pillars approach and to seek more physically-realistic interstellar dust analogues. The analy- sis of the pre-solar grains extracted from meteorites, interplanetary dust particles and from the Stardust mission, and the interpretation of x-ray scattering and absorption observations, supports the view that our current view of the interstellar dust composition(s) is indeed too naive. The aim of this review is to point out where our current views are rather secure and, perhaps more importantly, where they are far from secure and we must re-think our ideas. To this aim ten as- pects of interstellar dust will be scrutinised and re-evaluated in terms of their validity within the current observational, experimental, modelling and theoretical constraints. It is concluded from this analysis that we really do need to re-assess many of the fundamental assumptions relating to what we think we really do know about interstellar dust. In particular, it is clear that unravelling the nature dust evolution in the interstellar medium is perhaps the key to significantly advancing our current understanding of interstellar dust. ...
What an infra-nilmanifold endomorphism really should be  [PDF]
Karel Dekimpe
Mathematics , 2010,
Abstract: Infra-nilmanifold endomorphisms were introduced in the late sixties. They play a very crucial role in dynamics, especially when studying expanding maps and Anosov diffeomorphisms. However, in this note we will explain that the two main results in this area are based on a false result and that although we can repair one of these two theorems, there remains doubt on the correctness of the other one. Moreover, we will also show that the notion of an infra-nilmanifold endomorphism itself has not always been interpreted in the same way. Finally, we define a slightly more general concept of the notion of an infra-nilmanifold endomorphism and explain why this is really the right concept to work with.
What really causes large price changes?  [PDF]
J. Doyne Farmer,Laszlo Gillemot,Fabrizio Lillo,Szabolcs Mike,Anindya Sen
Physics , 2003,
Abstract: We study the cause of large fluctuations in prices in the London Stock Exchange. This is done at the microscopic level of individual events, where an event is the placement or cancellation of an order to buy or sell. We show that price fluctuations caused by individual market orders are essentially independent of the volume of orders. Instead, large price fluctuations are driven by liquidity fluctuations, variations in the market's ability to absorb new orders. Even for the most liquid stocks there can be substantial gaps in the order book, corresponding to a block of adjacent price levels containing no quotes. When such a gap exists next to the best price, a new order can remove the best quote, triggering a large midpoint price change. Thus, the distribution of large price changes merely reflects the distribution of gaps in the limit order book. This is a finite size effect, caused by the granularity of order flow: In a market where participants placed many small orders uniformly across prices, such large price fluctuations would not happen. We show that this explains price fluctuations on longer timescales. In addition, we present results suggesting that the risk profile varies from stock to stock, and is not universal: lightly traded stocks tend to have more extreme risks.
What is and What should be Time?  [PDF]
Hitoshi Kitada,Lancelot R. Fletcher
Physics , 1994,
Abstract: The notions of time in the theories of Newton and Einstein are reviewed so that certain of their assumptions are clarified. These assumptions will be seen as the causes of the incompatibility between the two different ways of understanding time, and seen to be philosophical hypotheses, rather than purely scientific ones. The conflict between quantum mechanics and (general) relativity is shown to be a consequence of retaining the Newtonian conception of time in the context of quantum mechanics. As a remedy for this conflict, an alternative definition of time -- earlier presented in Kitada 1994a and 1994b -- is reviewed with less mathematics and more emphasis on its philosophical aspects. Based on this revised understanding of time it is shown that quantum mechanics and general relativity are reconciled while preserving the current mathematical formulations of both theories.
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